A federal appeals court has blocked the execution of a Muslim inmate in Alabama after the state refused to allow his imam to be present at his death.

Domineque Ray, convicted of murdering a 15-year-old girl in 1995, was scheduled for execution on Thursday.

But his lawyers argued that the state infringed on his religious rights by denying his request for an imam over a chaplain during the execution.

The state has now appealed the stay to the US Supreme Court.

A three-judge panel reversed an earlier court ruling and delayed Ray's death by lethal injection, writing in an opinion that Ray had a "powerful" claim against the state.

"The central constitutional problem here is that the state has regularly placed a Christian cleric in the execution room to minister to the needs of Christian inmates, but has refused to provide the same benefit to a devout Muslim and all other non-Christians."

According to the Alabama Department of Corrections (ADOC), Christian chaplain Chris Summers has witnessed nearly every execution since 1997.

Ray's complaint requests the court to not mandate the chaplain's presence in his execution chamber and to allow his imam instead, "so that he may receive spiritual guidance and comfort from a cleric of his own faith" at the time of his death.